1. Field of Invention
This invention relates to an electronic circuit module using electronic components which generate heat; and, more particularly, to an electronic circuit module adapted to be installed in the head portion of an LSI tester, or in an aircraft.
2. Description of the Prior Art
Semiconductor devices, such as LSIs, are evolving at a rapid pace, and their various functions and constructions have become increasingly complex. An LSI tester is used to test such semiconductor devices.
An LSI tester first applies a testing signal having various patterns to an LSI or device under test (called "DIRT") from a testing signal means. The tester then compares output data from the DUT with an expected value pattern which has been previously prepared according to the applied testing signal. In this manner, the acceptability of the DUT is judged. As the number of pins of the DUT increases, electronic circuits, called "numerous pin electronics" are installed in the head portion of the tester which applies the testing signal to the DUT. An electronic circuit module,on which the numerous pin electronics are installed, is required to be as thin as possible.
A similar requirement is imposed on electronic circuit modules which are used in aircrafts, where weights and sizes of components are important.
FIG. 1 is a conceptual illustration of a conventional electronic module which is used in an aircraft or in the head portion of an LSI tester. The module comprises a plurality of electronic components which generate heat.
In FIG. 1, a plurality of electronic components P3 are packed on a printed circuit board P1. Similarly, a plurality of electronic components are packed on another printed circuit board P2. Thin metal sheets P4 are placed in intimate contact with the printed circuit boards P1 and P2 (on side so that no label appears in the drawing), respectively. Cooling fins P5 are shaped to have corrugated cross sections, as depicted. The cooling fins are disposed between the two thin metal sheets P4 and brazed or adhesively bonded to their respective thin metal sheets. A spacer is positioned between the two printed circuit boards. A connector P7 is mounted at one end surface of the printed circuit hoard P1.
Cooling air is supplied Into passages formed by the cooling fins P5 of corrugated cross section, as well as into passages formed between each cooling fin P5 and the spacer P6, to dissipate heat generated by the printed circuit boards and also by the electronic components.
To increase the efficiency of heat dissipation, the surface area of the cooling fins must be increased. But, the spacing between the two boards P1 and P2 of FIG. 1, must be of a certain dimension. Thus, it is nearly impossible with the conventional device to reduce the thickness of the module in the thickness direction. This presents serious problems, especially where a large number of printed circuit boards are arranged in a restricted space, such as available in head of an LSI tester, for example.